Re "all of the mail was the usual, in my daughter's name, for the past several years, so no real change."

I've learned from my letter carrier that the person who puts the mail in your box doesn't even look at it. People at the local branch sort the mail, form it into packets, and put rubber bands around them. The carrier walks the route as fast as possible, shoving the packets into mail boxes. In fact, I have tried to catch him a couple times, and between the time I hear my mail arrive and the time I get out my front door, he is gone.

So the sorters don't know the house looks vacant, and the carrier doesn't know whose name has been on the mail all this time.